Dystonia can appear at any age and can be classified according to the age of onset as.
Infancy (birth to 2 years).
Childhood (3 to 12 years).
Adolescence (13 to 20 years).
Early adulthood (21 to 40 years)
Late adulthood (> 40 years).
Primary dystonia is most often seen in children or adolescents aged 7 to 15 years.